I work for a Metel Building producer in Arkansas, I run the Sub Arc Welder ( Beam Line ). We have for years used 600amp Lincoln welders for as long as I can remember. My question is this, We use in combanation 10gauge as a web and 1/4" X 5" mild steel for flanges, as a pretty much standerd ( Company money maker ) product and never had a lot of problems, now after all this time, the powers that be upgraded my two 600's to 1000amp welders, my wire feeders are all messed up now. At the end of a beam when I shut off the power to the NA5's (Controllers), both feeders instead of shuting down now feed in reverse.

Anyone have a clue??????????   We have allmost zero Maintiance here other than me and I am pretty good at the mechanical end but not the Electrical.
Any ideas or tips would be a huge help.